1. Field of the Invention
The apparatus of the present invention relates to locking swivels. More particularly, the present invention relates to a mechanical locking swivel positionable above the rig floor for allowing the reorientation of a bent sub during a directional drilling without having to withdraw a wireline that has been located within the drill string from above the rig floor.
2. General Background of the Invention
In the drilling of oil wells, one of the more frequent types of wells that are drilled are directional wells. Rather than have to drill a well vertically, often times because of the location of the pocket of hydrocarbons, or for other reasons, the direction of the well has to be altered or done in a direction off of the vertical and is termed a directional well. This is accomplished with the use of a type of a bent sub which is placed on the lower end of the drill string and the drill bit is rotated downhole via a motor known as a dynadrill. The bent sub, when it is oriented in a particular pre-determined orientation, will have the bit drill travel in that particular orientation as a directional well.
Quite often in the drilling process, the direction of the drill bit has been mis-oriented and has to be adjusted slightly in order to reorient the bit in the proper direction. In most cases, this can easily be accomplished by setting the drill string via the slips, and rotating the rotary table slightly so that the entire drill string is re-oriented and then drilling can resume at that orientation. However, in the instance when there is a wireline which has been fed down into the drill string, because the wireline is usually fed through a side entry sub apparatus, the string cannot be rotated due to the fact that would put stress on the wireline itself, which may result in the wireline being cut and the tool at the end of the wireline could be lost within the well bore, which would result in the tool having to be retrieved if possible. This is time consuming and expensive and requires that the well be shut down in order to do so. However, in the current state of the art, in order to reorient the drill bit while a wireline is downhole, the tool at the end of the wireline has to be retrieved from the well. Next, the drill string has to be reoriented in the proper direction and then the wireline would be re-fed down into the drill string for undertaking its work downhole. Again, this is time consuming and results in loss of rig time. There are also devices known in the industry which attempt to provide a means by which the drill string can be oriented without having to orient the upper portion of the drill string above the rig floor where the wireline is being fed. These types of tools are known as swivels, and to some extent are successful to a certain point.
Therefore, there is a need in the art for a tool that can be easily engaged and disengaged at that point between the side entry sub from where the wireline is being fed and the lower drill string, so that the orientation of the drill bit can be changed without placing stress on the wireline.